Metallic filaments for incandescent electric lamps.



' ner, which substances act as: bin

STATES PATENT orrrcn. T

.KABL FABKAS, NEW YORK,

1T0 Drawing.

To all'wlwm it'may concern:

Be it known that I, K-Ann FARKAS, a citi- Zen of the Kin dom of Hungary, and a resident of New of New York, have invented certain new and useful Improvements in Metallic Filaments for Incandescent Electric Lamps, of which the following is a specification.

j This invent-ion has reference to a novel l0 nents for incandescent electric lamps.

process of, producing. so called-metallic fila- I It pertains I particularly j to improvements in the roductlonof metallic filaments pre paredby pressure from fine. wder of a highly refractory chemical e ement with glutinous substances in the well known manding materials. Such chemical elements adaptedfor this purpose "are for instance, tungsten, molybdenum, osmium, chromium or ruthenium, etc. The metallic filaments thus prepared containcarbonaceous material because the glutinous substances are of organic origin. During theprocessof producin such filaments the=glutmous substance is ecomposed by heat and carbon set free which then forms part of-the filament. Carbon, as is well known, consumes about three times the of fine powder of'such h electric current to become incandescent as the pure highly refractory chemical element of which the filament is essentially composed.

Therefore the finished filament pressed out lghly refracto chemical element should beaentirely from carbon.

I have discovered that metallic filaments prepared with glutinous organic binders may be freed entirely from carbon by embedding them in metallic oxids preferably the oxids of the'earthy metals which must be in form offine powder, heating them therein .to a high temperature and finally heating them preferab y to. a-highervtemperature in the presence of oxygen gas. These filaments are embedded in a mixture of aluminum ox-i'd and cerium oxid or they may be embedded in a mixture of aluminum oxid, magnesium oxid,- and cerium oxid. During the process of heating, the glutinous substance is carbonized and decomposed and forms carbon in statu nascendi which, however, owing to the.presence of the above oxids does not act on the highly refractory element of the filament but acts on the oxids.

The proportions in which the oxids are N. 'Y., ASSIGNOB OF ONE-HALF TO 01 YORK, 11'. Y.

ork, inthefcounty and State transforms I completel em? v; winmms,

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7 A g Specification of Letters Patent. Pat ted Nov. 14, 1911.

" Application filed August 9, 1909. Serial No. 511,998.

employed are substantially as follows: About 90% of aluminum oxid is mixed with about" 10% of cerium oxid or about of aluminum oxid is mixed with aboutabout 20% ded in. the mixture of metal oxids, the box contalnmg them is evacuated and then gradually heated upto "about 1500 F When this temperature has been reached oxygen is introduced into the box from a reservoir in which the oxygen is preferably under some pressure. The quantity of oxygen introduced is measured on the barometer tube which indicates the vacuum. So much of oxygen is introduced that the mercury in the barometer tubesinks about 1% inches. 'The filaments are now further heated in the atmosphere of oxygen and the temperature is increased to about 2200 F.

During this time all carbonaceous material from the binder and all carbon resulting therefrom is combusted leavmg a pure metallic .filament of'homogeneous structure and then the oxygen begins to oxidize slightly the surface of the pure metallic filament pro-' ducing thereon an exceedingly fine coating i of oxid of the highly refractory elementaly substance of which the filament is compos When such filament is embodied in a lamp the fine coating of oxid is rendered incandescent together with the entire filament.

The heating of the filaments in the vae-- uum in an atmosphere of oxygen any trace of car 0- naceous material an carboninto carbon dioxid and further tends to oxidize or combust any other impurity which mi ht mechanically adhere-to the filaments. bus the filament prepared according to the above process is entirely free from 'carbonand on the surface of same a veryfine coating of oxid is produced. during the last stage of this process.

. I claim as myinvention:

1. The process of producing metallic filaments for incandescent electric-lamps consisting in embedding shaped filaments of a highly refractory chemical element containing a glutinous -organic binder in a mixture of metallic oxids, heatin same under exclusion of the air to a big temperature, andthen continuing the heating in the presence of oxy en.

2. T e process of producmg-metalhc filaments for incandescent electric lamps consisting in embedding shaped filaments of a highly refractory chemical element containing a glutinous organic binder in fine. powder;of oxide of the earthy metals, heating sanie under exclusion of the air to a big temperature, and continuing the heating up to 'a higher temperaturein the presence of oxygen.

31 The process of producing metallic filaments for incandescent electric lamps 'consisting in embedding shaped tungsten filaments containinga glutinous organic binder in a mixture of metallic oxids, heating same in 'vacuo to a high temperature, and then continuing .the heating to a higher temperature in the presence of some oxygen.

num oxid mixed with some ceriumoxid, heating same in 'vac'uo to a temperature of about1500 F., introducing some oxygen, and then heating :jsaid filamentsy-to about 6. The process of'producing metallic filaments for incandescerit electric laiiiiilps con sisting in preparing y ressure aments from fine powder-of a highly refractory chemical elementandia glutinous organic binder, embedding said filaments in aluminum oxid mixed with some cerium oxid, heating same in 'vacuo to a temperature of about 1500 F. andthen heating same in an atmosphere of oxygen up to a temperature of about 2200 F. v

7. The process of urifying metallic filaments containing car on consisting in heating same in vacuo to a temperature of about 1500 F. and then heating same in an extenuated atmosphere of oxygen up to a temperature of about 2,200 F. Signed at New York, N. Y., thls of August, 1909.

' a KARL FARKAS.

Witnesses:

LUDWIG K. BOHM, GUY V. WILLIAMs.

7th day 

